Method and retort for the distillation of solid hydrocarbonaceous materials



March 8', 1949.

L. c. HUFF 2,463,693 METHOD AND RETOBT FOR THE DISTLLATION OF SOLIDHYDROCARBONACEOUS MATERIALS Filed April 2o, 194e 2 sheets-sheet 1 Y my):cy:

March 8, 1949. C HUFF METHOD AND RETORT FOR THE DISTILLATION OF FiledApril 20, 1946 SOLID HYDROCARBONACEOUS MATERIALS 2 Sheets-Sheet 2 Jollds(la/:9e

Patented Mar. 8, 1949 METHOD AND RETORT FOR DISTILLA- TION OF SOLIDHYDROCARBONACEOUS MATERIALS Lyman C. Huff, Evanston, Ill., assigner toUniversal Oil Products Company, Chicago, Ill.| a l corporation ofDelaware Application Aprii zo, 194s, serial No. 663,667'

(ci. 2oz-11s) i 1 10 Claims.

This invention relates to an improved type of distilling retort and animproved method of distillation for oil shales, tar-sands, coal andother solid types of hydrocarbonaceous materials.

Broadly, the invention comprises an improved method for recoveringvaporous and volatile matter from crushed carbonaceous solids byconveying them serially through a plurality of adj acently disposeddistillation zones, passing hot gases in heat exchange relationship withthe distillation Zones and withdrawing distillation productsindependently from each of the distillation zones. Large pieces or lumpsof only partially spent solid material are separated from the iines inthe last of the series of distillation zones and recycled to one of theintermediate distillation zones for reheating, while the fine materialis discharged from the last distillation zone and from the retort.

It is an object of this invention to eiect an eiilcient and continuousmethod of distilling vaporous material from solid hydrocarbons such thatthe distillation products are recovered without being contaminated bycombustion gases or other direct heating gases.

A second object of the invention is to provide recycling means for thelarger pieces of solid material from which additional volatile materialmay be removed.

Another object, is to provide a number of contact zones, in a heatedretort, through which the carbonaceous material is passed serially andfrom which distillation products may be progressively withdrawn atvarious temperature stages, Without subjecting the lighter vapors to thedestructive effect of a higher-dlstillation temperature than necessary.

A still further object of the invention is to provide distillation zoneswhich may be entirely encompassed or surrounded by the heating mediumand are so constructed and operated that coke is substantially preventedfrom forming therein.

The improved continuously` distilling retort comprises a plurality oflongitudinal trough-like closed chambers in which there are rotatingshafts having screw conveying means to move the material therethroughfrom one chamber to the next. All of the trough-like distillationchambers are normally positioned in one horizontal plane in afurnace-like setting or housing, such that hot gases from. burners orother suitable heat supplying means may be brought into contact with thechambers which are suspended therein. Crushed oil shale or other solidhydrocarbons.- ceous material is charged to one end of the plurality ofchambers by automatic conveyor means, while at the other end of theunit, spent or ashlike material is removed from the unit. In the naldistillation chamber, at the discharge end of the retort, rake-liketeeth operate to screen out the large lumps or pieces of uncompletelydistilled solid material and pass them to a crusher where they arelreduced in size and then passed to a recycling conveyor which returnsthem to one of the intermediate distillation chambers. An outlet fordistillation products is provided at each of the independentdistillation zones or chambers in order that the distillation productsmay be withdrawn and passed to suitable'condensation and separationequipment.

, The recycling feature, whereby the partially spent material isseparated out and returned to the distillation chambers, is ofparticular advantage for efiiciently removing all vaporous and volatilematter from the material being charged.

from the erst to the iast cr nnai distillation zone.'

Thus, the volatile material is obtained in varying temperature rangesfrom the unit with the vapors being individually removed from each ofthe independent distillation chambers without being subjected to higherdistillation temperature than necessary. However, if it is so desired,the outlets or vapor lines may be grouped such that the first two orthree zones discharge to one condensing coil, the next two or threedischarge to a second condensing coil, etc It may thus be seen that thevapors from this retort may be obtained in a controlled manner and willbe in an uncontaminated' form, also, that the improved retort isconstructed and arranged to allow for very ilexible operation,permitting highly eillcient distillation of solid carbonaceousmaterials.-

Further advantages in the retort and in the method of operation will beapparent upon rei'- erence to the accompanying drawings and the fol.lowing description thereof.

Figure 1 is a cross-sectional elevational view through a simplified formof the improved retort. while Figure 2 shows a different cross-sectionalelevational view through the retort as indicated by the line 2-2 Figure1 of the drawing.

Figures 3 and 4 show sectional views of a portion of the finaldistillation chamber and serve 'to illustrate the method of removing thepieces oi' only partially spent solid material and transferring themthrough a crusher tera recycling conveyor.

Figure is a sectional and side elevational view at the end of the finaldistillation zone, as indicated by line 6-5 in Figure 3 of the drawing,indicating the relationship of the crusher rollers and inclined conveyorsuitable for recycling the incompletely distilled lumps of solidmaterial to an intermediate distillation chamber.

Figure 6 ofthe drawing is a sectional view at the end of the recycleconveyor system, at the point where the crushed and returned large lumpsor particles re-enter the distillation chambers, as indicated by line6-6 in Figure 1 of the drawing.

Figure 'l shows diagrammatically the flow of the solid material throughthe improved distillation retort.

Referring now to Figures l and 2 of the drawing, the furnace-likehousing I serves to enclose and separate a plurality of closeddistillation chambers, 2, which are positioned substantiallyhorizontally across the furnace and are separated one from anothersulciently to allow free circulation of hot flue gases around each ofthem. Each of the distillation chambers 2 have rounded trough-likebottoms which accommodate rotating screw conveyor shafts 3 and 4, whichin turn have paddle type conveyor blades 5 mounted thereon operating tocontinuously mix and propel forward the crushed shale or other solidmaterial. It should be noted that the blades 5 are mounted on the shafts3 to move material in one direction and on shaft 4 to move the materialin the opposite direction. Thus, the solid material is moved back andforth in each chamber and serially through each of the pluralitychambers. `The short conduit section 6 provided with means for taking upexpansion serves to connect adjacent distillation chambers 2 and topermit the transfer of solids from one to the other. A dividing plate 1in the center of each of the chambers, prevents the oppositely movingbeds of the material from being mixed in any one chamber, however, atone end of each of the chambers, the plate 1 is notched, so that thekicker plates 3 on the shafts 3 will transfer the material from onetrough to the other. Kicker plates 8 are also placed on the shafts 4, atthe opposite ends of the chambers, so that the material will betransferred through the short conduit 6 to the vnext adjacentdistillation chamber.

Crushed shale is charged to the top of the distillation retort by theelevator type of conveyor 9 and is then carried b y way of a helicoidconveyor I0 in duct II to a short transfer duct I2 which in turnconnects with the first distillation chamber 2 of the row within thehousing. The crushed material is` then conveyed serially through each ofthe chambers by means of the continuously revolving paddle typeconveyors within each of the distillation zones. The chambers 2 may besuspended from the housing I- by hangers I3 or supported in some othersuitable manner. The shafts 3 and 4 are positioned and supported bysuitable bearings I4 which are placed at each end of the chambers and atthe driven end, the end of the shafts project through the Wall of thehousing I in order to connect with a common transfer drive-shaft I5. Aworm gear I6 is mounted on the end, of each of theconveyor shafts 3 and4 while a series of worm sections I1 are mounted on the drive-shaft I5to mesh with the gears I6 such that each of the paddle conveyors andshafts 3 and 4 will be simultaneously rotated.

In the retort shown, heat for contacting diswhich are in turn connectedto suitable fuel supply lines 2l. Control valves 22 are placed in thefuel supply lines 2| in order to provide means for controlling the fuelsupply to burners I8 and thereby in turn control the amount of heat toeach of the distillation chambers 2, The hot flue gases flow upwardly tothe upper portion of the housing passing around each of the suspendlngdistillation chambers and are then discharged through a stack or outlet3 I.

In the final distillation chamber 2a, a special shaft 4a is providedwith a helicoid conveying blade 24 and tooth-like projections or rakes25 which are suitable for removing lumps or pieces of solid materialfrom the residual coarse and ne material, such that they may be crushedand recycled to one of the intermediate distillation chambers 2. InFigure 3 of the drawing, the partlalplan view serves to show how thesolid material is passed from paddle conveyor 3 in one trough to theconveyor blade 24 in the second trough. The rakes 25 will screen out andpush the coarse material through the connecting duct or passageway 26 toCrusher housing 34 having rollers 35 and then to a recycled conveyingtube 21 in which there is a helicoid conveyor 2B. Figure 4 of thedrawing shows an elevational crosssectional view through this sameportion of the unit as indicated by line 4 4 in Figure 3.

Referring again to Figure l of the drawing it may be seen that theconveyor tube 21 slopes upwardly, extending to a point above thetransversely positioned conveyor tube II wherein by means 0f thehelicoid conveyor I0 the crushed coarse material is carried to the shorttransfer duct 29 which is in communication with one of the intermediatedistillation zones 2. The partition plate 30 in the tube I I' preventsthe recycled material from continuing forward and mixing with the freshcrushed solid material entering by way of the charge conveyor 9. Thefine spent or ash-like material in the final distillation chamber 2a isconveyed forward by the helicoid conveyor 4a to the end of the chamberwhere it is discharged through an outlet duct 32. One end of the shaftI0 extends through the wall of the housing I, and is provided with agear or pulley 33 such that the shaft may be continuously rotated. Anysuitable type of engine or motor and drive equipment` (not shown) may beused to operate the drive shaft I5. the crusher rolls 35, the inclinedhelicoid conveyor 28, and the conveyor shaft I0.

Referring now to Figure 5 of the drawing, it may be still further notedhow large particles or lumps from distillation chamber 2a may beselectively discharged therefrom by means of the rakes 25. The lumpsseparated by the rakes 25v n that a crushed oil-shale is to be distilledtherein.

'I'he crushed shale is fed to the\elevator conveyor 9 which in turnpasses it to the preheating conveyor tube Il and as it is transferred tothe first distillation zone 2, it is heated by the outgoing flue gaseswithin the housing I. below the rst few distillation chambers 2 aremaintained at a 'relatively low heat output so that Aa mild distillationis effected in the first few zones. However, the burners are controlledso that the distillation zones become increasingly hotter across thewidth of the retort and the material therein is subjected to relativelyhigh distilllng and cracking temperatures in the last few zones. As thematerial is slowly propelled through each of the zones, the volatile andvaporous matter is driven ofi' and the solids are broken down into anash-like material by the action oi heat, as well as the action of theblades 5. In order to accomplish the eilioient removal of all vaporousmaterial and the break-down of all .o1 the solid material, the rakes 25,crusher rolls 35, and recycling conveyors 2'i and ii provide means forreturning the large lumps or pieces to an intermediate chamber forfurther heating and distillation.

The distillation products are withdrawn by way of outlet lines 23 andmay be sent separately to condensing and separating equipment (notshown) or, of course, the lines may be combined such that the productsof the first two or three zones are commingled, the products of the nexttwo or three commingled, etc. prior to their passage to the separatingequipment. It should be noted, that since the distillation chambers 2are entirely surrounded by hot gases, that there will be very littlecondensation or coking of carbonaceous materials within the retorts,'due to cool surfaces.

With some materials it may be unnecessary to recycle any part of thematerial and a continuous once-through operation may be employed. The

removal of the rake-like teeth 25 on shaft la allows the material to bepassed directly i'rom the retort withoutany recycling and therebyail'ect a once-through operation.

The flow diagram of Figure 'l shows by means of the lines and arrows thepath of the solid carbonaceous material. The crushed solid material ischarged first to a preheating zone in one end of duct il and passestherefrom into the first or end distillation chamber of a plurality ofdistillation zones or chambers 2, all of which are con-A nected in amanner to pass the solid material serially through the plurality ofadjacent chambers 2 to the last chamber 2a. At the nal distillationchamber 2a, the large particles and lumps are separated and crushedwhile the tine, primarily ash-like material is discharged from theretort by the helicoid conveyor 24 and duct 32. The separated andcrushed material for redistillation passes from the crushing zone to theThe burners I8 zones and recycling the remaining portion of inclinedconveyor 21, which in turn carries the material to the recycle portionof duct Il in order that it may be returned to one of the intermediatedistillation zones.

It is not intended to limit the operation of this retort to oil-shalesonly, for it is withinthe scopef of this invention to use all type?, ofcrushed solid carbonaceous materials. It is also contemplated thatvarious structural and mechanical change/s may be made in connectionwith the construction details, without deviating from the improvedarrangement and method of operation which comprises the invention.

I claim'as'my invention:

1. A method for recovering vaporous and volatile material from crushedhydrocarbonaceous solids which comprises conveying said solids seriallythrough a plurality of distillation zones,

passing hot gases in indirect heat exchange rela.-

tionship with said distillation zones, withdrawing distillation productsindependently from each of said distillation zones, separating andremoving lines from the solid material present in the last of saidplurality of distillation zones and recycling the remaining portion ofsolids to an intermediate distillation zone of said plurality of passinghot gases in indirect heat exchange relationship with said distillationzones, controlling l distribution of said hot gases to provide anincreasing heat intensity from the ilrst charged distillation zone tothenal distillation zone, withdrawing distillation. products independentlyfrom each of said distillation zones, separating and removing fines fromthe solid material present in the last of-said plurality of distillationsolids to an intermediate distillation zone of said plurality of zonesfor reheating.

3. A method for recovering vaporous and volatile material from crushedhydrocarbonaceous solids which comprises preheating said solids inindirect heat exchange relationship with a hot gaseous medium, passingsaid preheated solids to a plurality of -distillation zones, conveyingsaid solids serially through said distillation zones, passing a hotgaseous medium in indirect heat exchange relationship with saiddistillation zones, controlling distribution of said hot medium toprovide an increasing heat intensity from the i'lrst chargeddistillation zone to the last of said plurality of-distillation zones,withdrawingdistillatlon products independently from each of saiddistillation zones, separating and removing nes from the solid materialPresent in the last of said plurality of distillation zones andrecycling the remaining portion of solids to an intermediatedistillation zone of said plurality of zones for reheating.

4. A retort for the distillation of solid hydrocarbonaceous materialwhich comprises a furnace-like housing. means for passing hot gasesthrough said housing, a plurality of enclosed distillation chamberspositionedl adjacent one another in the upper portion of said housing,means for conveying crushed solid material to the first of saidplurality of chambers and passing said material serially through each ofsaid chambers.

f means for separating and removing 'fines from chamber of saidplurality of chambers and a recycling conveyor in communication withsaid last distillation chamber, means for transferring the remaininglarger solid particles to said recycling conveyor, said conveyor beingconstructed and arranged to carry said larger particles to anintermediate distillation chamber.

5. A retort for the distillation of solid hydrocarbonaceous materialwhich comprises a furnace-like housing. means for passing hot gasesthrough said housing, a plurality of enclosed distillation chamberspositioned adjacent one another in the upper portion of said housing,means for conveying crushed solid material to the rst of said pluralityof chambers and passing said material serially through each of saidchambers,

'means for separating and removing fines from the solid material presentin the last distillation chamber of said plurality of chambers, crusherrolls and a recycle conveyor in communication with said lastdistillation chamber, said rolls being positioned between said lastchamber and the recycle conveyor, and said recycle conveyorcommunicating with an intermediate distillation chamber.

6. A retort for the distillation of solid hydrocarbonaceous materialwhich comprises` a iurnace-like housing, a firing oor in the lowerportion of said housing, a plurality of fuel burners spaced across saidfloor, a plurality of enclosed distillation chambers positionedhorizontally and adjacent one another in the upper portion of saidhousing, means for conveying crushed solid material to the i'lrst ofsaid plurality of chambers and passing said material serially througheach of said chambers, a recycling conveyor in communication with thelast of said plurality of distillation chambers, means for separatinglarge solid particles from ilnes in the last of said chambers, saidseparating means being constructed and arranged to transfer said largeparticles to said recycling conveyor and to discharge nes from saidretort, said recycling conveyor communicatlng withA one of theintermediate distillation chambers of said plurality of chambers.

7. A retort for the distillation of solid hydrocarbonaceous material asdescribed in claim 5y further characterized in that said fuel burnerswithin said housing are arranged and mechanically controlled to providea varying intensity of heat below each distillation chamber. y

8. A retort for the distillation of solid hydrocarbonaceous materialwhich comprises a furnace-like housing, a ring-iloor in the lower porofchambers, sa'id preheating tube operating to carry solid material fromoutside said retort to the first of said distillation chambers,conveying and mixing blades in each of said chambers operating to passsaid solids serially through each chamber and from one chamber to thenext, means for separating and removing fines from the solid materialpresent in the'last distillation chamber of said plurality of chambersand a recycling conveyor in communication with said last distillationchamber, meansfor transferring the remaining larger solid particles tosaid recycling conveyor, said conveyor being constructed and arranged tocarry said larger particles to an intermediate distillation chamber.

9. A retort for the distillation of solid hydrocarbonaceous materialwhich comprises a furnace-like housing, a firing-floor in the lowerportion of said housing, a plurality of elongated enclosed distillationchambers positioned horizontally and adjacent one another in the upperportion of said housing, an expansible connecting duct between each ofsaid chambers, a preheating tube within said housing having an internalhelicoid conveyor blade therein positioned above and transverse to saidplurality of chambers, said preheating tube operating to carry solidmaterial from outside said retort to the first of said distillationchambers, two longitudinal trough-like sections formed in the lowerportion of each of said distillation chambers, a rotatable shaft havingpaddle type conveyor blades in each of said trough-like sections, saidpaddle type conveyors being constructed and arranged to pass said solidmaterial in opposite directions therein and serially from one chamber tothe next, projecting ends from each of said rotatable shafts in saiddistillation chambers, a drive-shaft positioned out? side of saidhousing and mechanically connecting with each of said projecting ends,means for separating and removing fines from the solid material presentin the last distillation chamber of said plurality of chambers and arecycling conveyor in communication with said last distillation chamber,means for transferring the remaining larger solid particles to saidrecycling conveyor, said conveyor being constructed and arranged tocarry said larger particles to an intermediate distillation chamber.

10. 'I'he retort as dened in claim 8 further characterized in that saidmeans for separating and removing fines from the solid material in saidlast distillation chamber comprises a rotatable shaft in said lastchamber and rake-like members and avhelicoid conveyor blade mounted onsaid shaft.

LYMAN C. HUFF.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

